Mini-fans of this kind contain an electronically commutated motor whose rotor drives a fan wheel. The latter takes in air through an air inlet opening, and that air is then blown out through one or more outlet openings, e.g. radial openings.
Arranged in the region of the air passage opening are one or more sensors, e.g. a Negative Temperature Coefficient (NTC) resistor at which the present air temperature is measured, or a sensor for the moisture content, quality, radioactivity, stuffiness, dustiness, etc. of the air. For example, air quality in a workplace could be maintained by keeping a particular gas or pollutant, such as carbon dioxide or methane or flammable fumes, below a predetermined threshold level. An air conditioning system, for example, can be controlled in accordance with data from such a sensor or sensors. Since the fan is so small, installation of such a sensor, e.g. an NTC resistor, as a discrete device, is difficult and also entails considerable cost. In addition, an electrical connection must be made from the sensor installation location to a connector of the fan, which results in additional labor and material costs.